Guide to identification of Lumbrineridae (Polychaeta) - NTNU

Lumbrineridae in Norwegian and adjacent waters 2
Introduction
The lumbrinerids are generally long cylindrical bristle worms of small to medium size with rather
simple external morphology. The largest species in northern waters may reach a length of about 35
cm, but most species are 2-10 cm in length. They are mostly found in soft-sediment environments
where they burrow into the substrate. The lumbrinerids are largely considered to be carnivores, but
some species have been reported to feed on plant fragments or detritus (Fauchald & Jumars 1979).
The lumbrinerids belong in the eunicid group of polychaetes which is characterised by the
presence of a complicated jaw apparatus in the phaynx. The jaw apparatus is of the ‘labidognath’ type
(Orensanz 1990) and is basically similar to the jaws found in Eunicidae and Onuphidae. In traditional
faunal works the eunicid group has been treated as an order (e.g. Fauchald 1977, Hartmann-Schröder
1996), whereas in newer taxonomy the group has been placed without particular rank within the main
division Aciculata (Rouse & Pleijel 2001).
The most important taxonomic characters are found in jaw structures, types and shapes of
chaetae, and shape of respiratory lobes. Jaw characters have been extensively used for definition of
genera in recent years, which has lead to a more stable and consistent system for species classification
in the family. As a consequence, several new genera have been erected whereas extant genera have
been redefined (see Orensanz 1973, 1990; Frame 1992; Carrera-Parra 2006a). Orensanz (1990), Frame
(1992) and Hilbig (1995) have accounted for the taxonomic history of the family and have discussed
the importance of the diagnostic characters.
Morphology
The lumbrinerids have a long cylindrical body with generally similar segments (Figure 1). In most
species the width is gradually tapering towards the pygidium. The prostomium is well-developed and
is usually without eyes and appendages, but in some genera small occipital antennae may be found in
the fold between prostomium and periostomium. The peristomium consists of two rings (not true
segments) without parapodia and chaetae. Tentacular cirri are absent. The following chaetigers carry
parapodia which are mostly uniramous, but often a bundle of thin notoaciculae and a short knoblike
notopodium are found. Ventral cirri are absent. Chaetae include simple limbate chaetae, composite
spinigers, and simple and composite hooded hooks (Figure 1).
Figure 1. Lumbrineridae: anterior body (Lumbrineris), parapod from anterior body (Lumbrineris), chaetae
(limbate chaeta, composite spiniger (Lumbricalus), long-bladed simple hook, multidentate composite hook,
bidentate hook (Lumbrinerides), simple multidentate hook)
The maxillae consist of a pair of posterior carriers and four or five pairs of maxillary plates (Figure 2).
The carriers are broad, mostly short, and are attached to the most posterior pair of maxillae (mx I) by a
firm ’click-joint’ connection (labidognath arrangement). The maxillary plates are usually referred to
by numbers (roman numerals) from I to V (note that different numbering systems may be found in the